In the construction of electronic circuits and/or devices, a material of choice in many applications is aluminum nitride. Specifically, in many applications it is desirable to utilize aluminum nitride substrates because aluminum nitride exhibits a low coefficient of thermal expansion and high thermal conductivity as compared to, for example, alumina substrates.
Examples of prior art dielectric materials for use in conjunction with aluminum nitride may be found in Hang et al., U.S. Pat. Nos. 4,808,673 and 4,830,988. U.S. Pat. No. 4,808,673 discloses for example a dielectric ink including a glass composition comprising 15%-25% ZnO, 10%-25% MgO, 3%-12% BaO or SrO. 5%-20% Al.sub.2 O.sub.3, 35%-50% SiO.sub.2, 0.5%-3% P.sub.2 O.sub.5 and 1%-5% ZrSiO.sub.4. U.S. Pat. No. 4,830,988 discloses a dielectric ink including a glass composition comprising 25%-31% MgO, 9%-18% BaO, 10%-18% Al.sub.2 O.sub.3, 10%-15% B.sub.2 O.sub.3, 24%-34% SiO.sub.2, 0.6%-0.8% P.sub.2 O.sub.5, 2.5%-4.5% ZrSiO.sub.4, 0%-2% Sb.sub.2 O.sub.3 and 0%-0.3% CeO.sub.2.
New dielectric materials are continually being sought which provide improved thermal and dielectric properties, and a better coefficient of thermal expansion (CTE) with AlN substrates over a wide range of temperature (and no change of CTE upon refiring which could result in warpage of the aluminum nitride substrate).